MEP805B Generator High Oil Pressure issue

[MSMOG]

Just picked up a surplus MEP805B. Hopefully, this post is not premature. I've seen some posts about low oil pressure, but I couldn't find any posts on high oil pressure. Unit looks good, low hours, supposedly works... Initially, I ran into a fuel level sending unit issue. It was corroded to the point it won't work. We bypassed it, and I have one on order. Next I got an error message about low oil pressure. No leaks, oil level good, so I ordered a replacement oil pressure switch. I have ordered a new oil filter, but it's not here yet, so I have NOT changed the oil yet. The factory oil switch is 4 wire, 100 psi. I thought I was getting a new 4 wire, but I ended up with a 3 wire. I decided the 4th wire was a ground and not essential (yes, I do know what "assume" means), so I wired in the 3 wire switch (red, black and white). This may very well be my problem, so I am sourcing a 4 wire switch now. However, with the new 3 wire switch, the generator did fire up without any more low oil errors. However, the oil pressure started reading at 102 psi, and I got a high oil pressure error (oil pressure gauge maxes out at 100). This error/fault did NOT result in a shutdown. Everything else looked good and generator produced power properly. I am going to change the oil and oil filter and probably also get a 4 wire switch. Anybody else have any thoughts? Anybody else run into high oil pressure? What should standard running oil pressure be? I'm thinking around 60 psi. Generally speaking, high pressure could be caused by a blockage somewhere in the system, or the pressure relief valve stuck could be closed, or it could be the wrong or a bad sending unit. Here is the 3 wire I ordered. Based on the spec sheet that I saw, I assumed it was either 4 or 5 wires.
https://www.te.com/commerce/Documen...pdfEnglishENG_DS_MSP300_A2.pdfCAT-PTT0016

 

[Guyfang]

Have you downloaded the TM yet? Reading the operators manual will tell you things like what normal oil pressure should be.

When you ordered the replacement " oil pressure switch", did you test the old one? How did you order the new one? Did you order it after looking at the parts tm? What criteria did you use to order it? What part number or NSN did you use?